G.N. Lewis, at the University of California
at Berkeley devised a simple way to understand the nature of
the chemical bond in both ionic and molecular compounds. His
method rests upon focusing on the valence electrons of the elements.
He represents these valence electrons as "dots" around
the four sides of the elemental symbol.

Recall, it is the valence electrons that are
involved in most chemical reactions. Therefore, these Lewis electron-dot
symbols should help us understand the chemical properites of
these elements.